MMA superstar Conor McGregor is back to his usual antics: amusing his fans by throwing online shade at the expense of fighters he has faced.

On his Instagram, The Notorious once again took a shot at retired boxing legend Floyd Mayweather Jr., who has recently been teasing a potential debut in the Octagon. But this time around, McGregor decided to involve old rival and current UFC featherweight champion Max Holloway into the mix.

The "When there is no referee to save you" caption was obviously directed at Mayweather, who beat McGregor during his multimillion dollar boxing debut last year. Meanwhile, the accompanying photo featured McGregor palming Holloway’s face.

McGregor’s move quite literally added insult to injury for Holloway, who dropped out from his UFC 222 title defense due to a leg injury over the weekend. Of course, the equally vocal champion wasn’t just going to let this slide as he fired back with his own witty retort.

Both fighters shared the Octagon back in 2013 with McGregor coming out as the eventual winner. Since then, Holloway has been killing it after picking up the featherweight title along with 12 consecutive victories. On the other hand, McGregor hasn’t fought in an MMA match since facing Eddie Alvarez over a year ago.